Covering his tracks by claiming she died? You don't see anything wrong with that if that is what happened? Why would that be a better idea then just coming clean? Also, he did a bit more than just claiming she died.

There's a chance that it was all created for publicity which is kind of sick.

then is Mauia on it as well?

the character Lennay Kekua seems to predate Manti's rise to fame. It seems that there has been other marks to this hoax before, if you read what Mauia talks about (her father dying) you see a similar story as what Manti told. Very strange but she seems like some red herring used to lure all these polynesian hawaiian football players